Antibiotics (Side Effects, List, Types)

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What Are Antibiotics? Which Infections Do They Treat?

Antibiotics are among the most frequently prescribed medications in modern medicine. Antibiotics cure disease by killing or injuring bacteria. The first antibiotic was penicillin, discovered accidentally from a mold culture. Today, over 100 different antibiotics are available to cure minor, and life-threatening infections.

Although antibiotics are useful in a wide variety of infections, it is important to realize that antibiotics only treat bacterial infections. Antibiotics are useless against viral infections (for example, the common cold) and fungal infections (such as ringworm). Your doctor can best determine if an antibiotic is right for your condition.

What Are the Side Effects of Antibiotics?

Antibiotics may have side effects. Some of the more common side effects may include:

  • Soft stools or diarrhea
  • Mild stomach upset

You should notify your doctor if you have any of the following side effects:

What Are Symptoms of An Allegic Reaction to An Antibiotic?

Some people are allergic to certain types of antibiotics, most commonly penicillin. If you have a question about a potential allergy, ask your doctor or pharmacist before taking the medicine.

Allergic reactions commonly have the following symptoms:

  • Shortness of breath
  • Rash
  • Hives
  • Itching
  • Swelling of the lips, face, or tongue
  • Fainting

7 Types of Antibiotics

Although there are well over 100 antibiotics, the majority come from only a few types of drugs. These are the main classes of antibiotics.

  1. Penicillins such as penicillin and amoxicillin
  2. Cephalosporins such as cephalexin (Keflex)
  3. Macrolides such as erythromycin (E-Mycin), clarithromycin (Biaxin), and azithromycin (Zithromax)
  4. Fluoroquinolones such as ciprofolxacin (Cipro), levofloxacin (Levaquin), and ofloxacin (Floxin)
  5. Sulfonamides such as co-trimoxazole (Bactrim) and trimethoprim (Proloprim)
  6. Tetracyclines such as tetracycline (Sumycin, Panmycin) and doxycycline (Vibramycin)
  7. Aminoglycosides such as gentamicin (Garamycin) and tobramycin (Tobrex)

Most antibiotics have two names, the trade or brand name, created by the drug company that manufactures the drug, and a generic name, based on the antibiotic's chemical structure or chemical class. Trade names such as Keflex and Zithromax are capitalized. Generics such as cephalexin and azithromycin are not capitalized.

Each antibiotic is effective only for certain types of infections, and your doctor is best able to compare your needs with the available medicines. Also, a person may have allergies that eliminate a class of antibiotic from consideration, such as a penicillin allergy preventing your doctor from prescribing amoxicillin.

In most cases of antibiotic use, a doctor must choose an antibiotic based on the most likely cause of the infection. For example, if you have an earache, the doctor knows what kinds of bacteria cause most ear infections. He or she will choose the antibiotic that best combats those kinds of bacteria. In another example, a few bacteria cause most pneumonias in previously healthy people. If you are diagnosed with pneumonia, the doctor will choose an antibiotic that will kill these bacteria.

Other factors may be considered when choosing an antibiotic. Medication cost, dosing schedule, and common side effects are often taken into account. Patterns of infection in your community may be considered also.

In some cases, laboratory tests may be used to help a doctor make an antibiotic choice. Special strains of the bacteria such as Gram stains, can be used to identify bacteria under the microscope and may help narrow down which species of bacteria is causing infection. Certain bacterial species will take a stain, and others will not. Cultures may also be obtained. In this technique, a bacterial sample from your infection is allowed to grow in a laboratory. The way bacteria grow or what they look like when they grow can help to identify the bacterial species. Cultures may also be tested to determine antibiotic sensitivities. A sensitivity list is the roster of antibiotics that kill a particular bacterial type. This list can be used to double check that you are taking the right antibiotic.

Only your doctor can choose the best class and the best antibiotic from that class for your individual needs.

How Should I Take Antibiotics?

It is important to learn how to take antibiotics correctly. Read the label to see how many pills to take and how often to take your medicine. Also, ask your pharmacist if there is anything you should know about the medication.

An important question to ask is how the medication should be taken. Some medications need to be taken with something in your stomach such as a glass of milk or a few crackers, and others only with water. Taking your antibiotics incorrectly may affect their absorption, reducing or eliminating their effectiveness.

It is also important to store your medication correctly. Many children's antibiotics need to be refrigerated (amoxicillin), while others are best left at room temperature (Biaxin).

Take your entire course of antibiotics. Even though you may feel better before your medicine is entirely gone, follow through and take the entire course. This is important for your healing. If an antibiotic is stopped in midcourse, the bacteria may be partially treated and not completely killed, causing the bacteria to be resistant to the antibiotic. This can cause a serious problem if those now-resistant bacteria grow enough to cause a reinfection.

What Drugs Interact with Antibiotics?

Antibiotics may have interactions with other prescription and nonprescription medications. For example, clarithromycin (Biaxin, an antibiotic) should not be taken with metoclopramide (Reglan, a digestive system drug).

Be sure a doctor and pharmacist know about all the other medications a person is taking while on antibiotics.

What Is Antibiotic Resistance? Am I At Risk?

One of the foremost concerns in modern medicine is antibiotic resistance. Simply put, if an antibiotic is used long enough, bacteria will emerge that cannot be killed by that antibiotic. This is known as antibiotic resistance. Infections exist today that are caused by bacteria resistant to some antibiotics. The existence of antibiotic-resistant bacteria creates the danger of life-threatening infections that don't respond to antibiotics.

There are several reasons for the development of antibiotic-resistant bacteria. One of the most important is antibiotic overuse. This includes the common practice of prescribing antibiotics for the common cold or flu. Even though antibiotics do not affect viruses, many people expect to get a prescription for antibiotics when they visit their doctor. Although the common cold is uncomfortable, antibiotics do not cure it, nor change its course. Each person can help reduce the development of resistant bacteria by not asking for antibiotics for a common cold or flu.

Reviewed on 11/20/2017

REFERENCE:FDA Prescribing Information.

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